I have a 1988 Ski-doo Formula Liquid 462,
It always ran great, I went on a three day trip and never had to change the plugs the whole time. I had put about 350 miles on it. I have always used the Ski-doo Rotax no mineral oil and it has always run excellent.
At the end of my three day trip, I was getting a little low with my injection oil. I couldn't find a Ski-doo dealer, so I had to put in a bottle of Castrol GTX in. Now for the past 3 times I have went out on the sled and after about 1-2 hours of riding, I am fouling out plugs, and losing lots of power.
I drained the oil, as much as I could and refilled it with the Ski-doo oil. It is still doing it.
Any input would be great!

;) Castrol GTX that is automobile oil, not 2 stroke. That would surely cause a fouling problem. I would take off the oil tank and clean it out and clean oil line out also. Maybe it would help?

It was a Castrol GTX Two-stroke oil, it was the correct kind.

Oil rarely causes fouling, usually carb or ignition issues. Make sure you are using the correct heat range plugs and that they are gapped properly. I would also make sure you have fresh gas. Are both cylinders fouling plugs or just one?

I am using NGK BR9ES which is what I normally use.
I actually didn't check the gap.
I'll have to check the gas as well, it should have been fine.

When the sled has the fouled plug and it is running, look at the coils. Somtimes you can see a spark jumping becasue its not getting to the plug.

All you need to do is shut of the machine and spray the coil and wire area with WD-40. Then start up. The machine will run perfectly till probably the next morning.

If you see a spark jumping you either have to change the plug wires or the coil if its a newer machine that you cant remove the plugs.

I dont think oil would make the diffrence.

Did the tempature change? Did you park your sled in a heated garage?

Also the Gap must be 100% dead on. If its not its a foul waiting to happen.

I never checked the gap, so its a possibility.
I do park it in a garage. I went from around zero degrees out to around 25-30 also.

Thanks for the info.

Originally posted by Machzzzz1@Feb 18 2003, 10:10 AM
When the sled has the fouled plug and it is running, look at the coils. Somtimes you can see a spark jumping becasue its not getting to the plug.

All you need to do is shut of the machine and spray the coil and wire area with WD-40. Then start up. The machine will run perfectly till probably the next morning.

If you see a spark jumping you either have to change the plug wires or the coil if its a newer machine that you cant remove the plugs.

I dont think oil would make the diffrence.

Did the tempature change? Did you park your sled in a heated garage?

Also the Gap must be 100% dead on. If its not its a foul waiting to happen.
Mach, could he isolate them with something if this is the problem? ???

Update:

I noticed today when it acted up, both plugs were dry.
So I then tried spraying WD-40 on the coil. Sure enough it starting sparking, just at the point, where one of the wires, goes into the coil. I then replaced that wire, and it still isn't right and that wire has hardly any spark compared to the other side.
I am going to get a new coil and change the wires.
Thanks for all the great info!!!